System and apparatus of controlling ring resonator operating points

Abstract

A method and system for locking the resonance frequency of ring resonators by using laser sources to emit a plurality of different wavelengths, applying a tagging signal to each of the wavelengths, multiplexing the tagged wavelengths using a wavelength division multiplexor, coupling the multiplexed tagged wavelengths onto a bus waveguide, detecting the multiplexed tagged wavelengths with a first photodetector disposed before a first ring resonator and a second photodetector disposed after a last ring resonator of a plurality of ring resonators, sending the signals detected by the first and second photodetector to a processor, which identifies and processes the tagging signals, generating a control signal for each ring resonator, by the processor and applying the control signals to phase shifters on each ring resonator of the plurality of ring resonators to tune and align the resonance wavelengths of the ring resonators with the wavelengths of the corresponding laser sources.

What is claimed is: 
     
       1. A photonics apparatus comprising:
 a plurality of laser sources, wherein each of the plurality of laser sources emit a different wavelength of light; 
 a laser source tagging system, wherein the tagging system applies tagging signals to the wavelengths emitted by the plurality of laser sources; 
 a wavelength division multiplexer configured to receive the tagged wavelengths; 
 a carrier in optical communication with the wavelength division multiplexer; 
 a bus waveguide integrated on a photonic chip; 
 a first photodetector associated with the bus waveguide, wherein the first photodetector is disposed before a plurality of ring resonators; 
 a plurality of ring resonators associated with the bus waveguide, wherein the plurality of ring resonators is disposed after the first photodetector; 
 a second photodetector associated with the bus waveguide, wherein the second photodetector is disposed after the plurality ring resonators; and 
 a processor configured to process the signals from the first and second photodetectors and generate a control signal to control the resonance wavelengths of the plurality of ring resonators. 
 
     
     
       2. The photonics apparatus of  claim 1 , wherein the number of ring resonators is equal to the number of laser sources. 
     
     
       3. The photonics apparatus of  claim 1 , wherein the ring resonators are ring modulators. 
     
     
       4. The photonics apparatus of  claim 3 , wherein the ring modulators are high-speed data modulators in optical communications. 
     
     
       5. The photonics apparatus of  claim 1 , wherein a phase shifter is integrated onto each of the plurality of ring resonators. 
     
     
       6. The photonics apparatus of  claim 1 , wherein the tagging system uses frequency division, and wherein the tagging signals applied to the wavelengths emitted by the light sources are different dithering signals for each wavelength. 
     
     
       7. The photonics apparatus of  claim 1 , wherein the tagging system uses time division, and wherein the tagging signals applied to the wavelengths emitted by the light sources are the same dithering signal applied to the wavelengths at specific time slots. 
     
     
       8. The photonics apparatus of  claim 1 , wherein the tagging system uses code division, and wherein the tagging signals applied to the wavelengths emitted by the light sources are dithering signals applied at specific codes. 
     
     
       9. The photonics apparatus of  claim 1 , wherein a hybrid time division and wavelength division tagging system is used. 
     
     
       10. The photonics apparatus of  claim 1 , wherein the wavelengths emitted by the laser sources are part of one band. 
     
     
       11. The photonics apparatus of  claim 1 , wherein the wavelengths emitted by the laser sources are divided into a plurality of bands. 
     
     
       12. The photonics apparatus of  claim 1 , wherein the number of laser sources is 40 arranged in a dense wavelength division multiplexing grid. 
     
     
       13. A method of locking the resonance frequency of ring resonators of a photonics apparatus, the method comprising the steps of:
 applying a tagging signal to each of a plurality of different wavelengths; 
 multiplexing the tagged wavelengths onto a single carrier using a wavelength division multiplexor; 
 coupling the multiplexed tagged wavelengths onto a bus waveguide; 
 detecting the multiplexed tagged wavelengths with a first photodetector disposed before a first ring resonator and a second photodetector disposed after a last ring resonator of a plurality of ring resonators; 
 sending the signals detected by the first and second photodetector to a processor, which identifies and processes the tagging signals; 
 generating a control signal for each ring resonator, by the processor; and 
 applying the control signals to phase shifters on each ring resonator of the plurality of ring resonators to tune and align the resonance wavelengths of the ring resonators with the wavelengths of the corresponding laser sources. 
 
     
     
       14. The method of  claim 13 , further comprising using laser sources to emit the plurality of different wavelengths. 
     
     
       15. The method of  claim 13 , wherein the tagging is accomplished by frequency division. 
     
     
       16. The method of  claim 13 , wherein the tagging is accomplished by time division. 
     
     
       17. The method of  claim 13 , wherein the tagging is accomplished by code division. 
     
     
       18. The method of  claim 13 , wherein the tagging is accomplished by time and code division.